1. Field of the Invention
The present invention relates to technology which improves the clarity of sound included in an audio signal.
Priority is claimed on Japanese Patent Application No. 2011-287793, filed on Dec. 28, 2011, the content of which is incorporated herein by reference.
2. Description of Related Art
When an audio signal, representing, for example, a movie or music, is played in the middle of the night, there are many cases in which the volume is turned down in consideration of neighbors. If the audio file, which is supplied from a source, has a low volume when the volume is turned down, it is difficult to hear reproduced sound. In particular, if volume is turned down when a movie is reproduced, it is difficult to hear low sound such as words because the range of volume (a dynamic range) is wide. In addition, if volume is turned up such that sound such as words or narration are easily heard, sound effects are reproduced at a high volume.
Here, technology has been proposed which compresses the dynamic range of the audio signal of a channel having a large number of voice components and corrects defects in which the voice components are buried in the volume of the audio signal of another channel after the compression is performed (for example, refer to Japanese Patent No. 4013906).
However, in this technology, if an audio signal includes a large number of components, such as sound effects or Background Music (BGM), in addition to voices, sounds are emphasized in addition to the voices, and thus the voices are not clear.